Controlling apparatus for highway crossing signals



1936- R. A. MCCANN ET AL 2,049,854

CONTROLLING APPARATUS FOR HIGHWAY CROSSING SIGNALS Filed April 5, 1935 INVENTORS Ronald A. M Cann and HenPg S. Young.

H is ATTORNEY Iatented Aug. 4, 1 9.36

Ni TABS CONTROLLING APPARATUS FOR HIGHWAY CRQSSING SIGNALS Ronald A. McCann, Swissvale, and Henry S.

Young, Willrinsburg,

Pa., assignors to The Union Switch & Signal Company, Swissvale, Pa... a corporation of Pennsylvania Application April 5, 1935, Serial No. 14,862

9 Claims.

the crossing from one direction after it has been initiated by another train approaching from the opposite direction even'if such other 5 train subsequently reverses its direction and clears the control section.

Other objects of our invention will become apparent as this specification progresses.

We will describe one form ofapparatus em- 20' bodying our invention, and will then point out the novel features thereof in claims.

I The accompanying drawing is a diagrammatic view illustrating one form of apparatus embodying our invention.

Referring to the drawing, the rails l and IA of a stretch of railway track X are divided by insulated joints 2 into relatively long sections AB and CD, which are separated from each other by a relatively short section BC. Section B-C includes the intersection of the railway and a highway designated by the refence character I-I. Each section is provided with a track circuit including a track relay designated by the reference character R with 3 a distinguishing sufiix connected across the rails l and M at one end of the section, and a track battery 3 connected across the rails at the other end of the section. The highway crossing H is .protected by a signal S of any suitable type such, for example, as a bell or a light signal or a combination of both, which signal is controlled by a signal control relay designated by the reference character K.

45 The sections AB and (3-D usually will be of such length as to provide adequate warning at the crossing for trains traveling at normal speed. The length of section B-C, as will be explained hereinafter, usually will be regulated in accordance with the speed of the trains and with the operating characteristics of certain relays.

Associated With each track relay R! and R3 is a repeating relay designated by the reference character J with the same suffix as that used in the reference character for the associated track relay.

Also associated witheach track relay RI and R3 is a stick relay designated by the reference character P with a suitable distinguishing suf- 5 As will be explained hereinafter, the stick relays Pi and P3 are effective to prevent operation of the crossing signal-by the relays R! and R3 when the sections AB and 0-D become occupied by trains receding from the crossing, and the track repeating relays J l and J3 are effective at times to prevent the closing of certain stick circuits for the relays PI and P3.

The reference character 4 designates a source of energy which, as here shown, is a battery.

The signal S is controlled only by a back contact 5 of relay K. Signal S, therefore, will be operated when relay K is released and back contact 5 becomes closed.

The signal control relay K is provided with a main control circuit and 'two auxiliary circuits. The main control circuit for relay K passes from battery l through front point of contact 1 of relay R2, front contact 6 of relay RI, front contact 9 of relay J I, frontcontact 8 of relay R3, front contact ll] of relay J3 and relay K back to battery 4. The first auxiliary circuit passes from battery 4 through front point of contact I of relay R2, front contact I I of relay PI and thence through front contact 8 of relay R3 over the same path just traced for the main control circuit. The second auxiliary circuit passes from battery 4 through front point of contact I of relay R2, front contact 6 of relay RI, front contact 9 of relay J I, front contact I2 of relay P3 and relay K back to battery 4. Signal control relay K, therefore, will become released at all times when relay R2 is released, and also will become released when relay RI or R3 becomes released provided the associated stick relay Pl or P3 is in its normal deenergized condition.

The repeating relay JI isv provided with a circuit which includes the front point of contact E3 of track relay RI. Likewise, the repeating relay J3 is provided with a circuit which includes the front point of contact M of track relay R3. Relays J l and J3, therefore, will be energized or released depending upon the condition of relays RI and R3, respectively.

Each stick relay PI and P3 is provided with one pick-up circuit and two stick circuits- The pick-up circuit for relay .Pl passes from battery 4 through back point of contact 14 of relay R3,

front contact I of relay J I back point of contact I6 of relay P3 and relay PI to battery 4. The pick-up circuit for relay P3 passes from battery 4 through back point of contact I3 of relay RI, front contact I1 of relay J3, back point of contact I8 of relay PI and relay P3 to battery 4. V The first stick circuit for relay PI passes from battery 4 through back point of contact I3 of relay RI, front contact I! of relay J3, front point of contact I8 of relay PI and relay PI to battery 4. The first stick circuit for relay P3 passes from battery 4 through back point of contact I4 of relay R3, front contact I5 of relay J I, front point of contact I6 of relay P3 and relay P3 to battery 4. The second stick circuit for relay PI passes from battery 4 through back point of contact I of relay R2, front contact I9 of relay PI. and relay PI to battery 4 The second stick circuit for relay P3 passes from battery 4 through back point of contact I of relay R2, frontcontact 20 of relay P3 and relay P3 to battery 4. Relay PI, therefore, will be picked up when relay R3 is released provided that relay J I and relay P3 are both in their normal positions, and will be maintained in that condition when relay R2 is released, or when relay RI is released provided relay J3 is in its normal position. Likewise, relay P3 will be picked up when relay RI is released provided that relay J3 and relay PI are both in their normal positions and will be maintained in that condition when relay R2 is released, or when relay RI is released provided relay J3 is in its normal position.

Having thus described the various parts of the apparatus embodying our invention, we will now explain their operation,

Under normal conditions, the track relays RI, R2 and R3 are all energized, the stick re- .lays PI and P3 are deenergized, and the repeating relays J I and J3 are energized. We will now assume that an eastbound train, that is, a train moving toward the right as shown in the drawing, enters section AB and causes the deenergization of track relay RI. This opens front contact 6 of relay RI and likewise opens the front point and closes the back point of contact I3 of relay RI. The opening of contact 6 interrupts the main controlcircuit for the signal control relay K. The deenergization of relay K establishes the signal operating circuit passing through back contact 5 of relay K, thereby causing the signal S to give warning to traflic on the highway H of the approaching train. The opening of front point of contact I3 releases relay J l, and the closing of the back point of contact I3 establishes the pick-up circuit for relay P3 through front contact I! of relay J3 and back point of contact I8 of relay PI.

When the train enters section BC, relay R2 will become released so that the front point of contact 7 will become opened and the back point of contact I will become closed. The opening of the front point of contact I will maintain the relay K in the deenergized position so that the signal S will continue to operate. ing of the back point of contact Igwill establish one stick circuit for relay P3 over its own front contact 20. When the train clears section AB, relays RI and J I will'become energized so that when the train enters section CD and releases relay R3 the other stick circuit for relay P3 will become established over the back point of contact I4 of relay R3, front contact I5 of The closrelay J I and the front point of contact I 6 of relay P3. As will be explained hereinafter, the relay R2 will remain in its deenergized position for a length of time sufficient to permit relay J I to become energized. The relay P3, therefore, will be maintained in its energized position, while the train traverses section CD so that the signal S will not operate although relays R3 and J3 will be released.

The section BC usually will be of such length that a train traveling at normal speed will maintain relay R2 in its deenergized condition, while the rear truck of such train istraversing section BC, for a period of time slightly greater than the total pick-up time of the relay RI or R3 and its associated repeater J! or J3. For example, the pick-up time of track relay RI will be of the order of 0.2 second and the pick-up time of the repeating relay J I will be of the order of 0.7 second or a total time of approximately 0.9 second. Assuming that the maximum speed is 60 miles per hour or 88 feet per second, the section BC usually will 'be not less than 100 feet long, so that the rear truck of a train traveling at this speed will not traverse section BC in less than approximately 1.1 seconds.

We shall next assume that will all of the apparatus in its normal condition, a train enters section CD from the right and then reverses its direction and clears section CD at the same instant another train enters section AB from the left. When the first train enters section C-D the operation of 'the signal will be initiated in a manner similar to that just described for an eastbound train. That is, the releasing of relay R3 will open the control circuit for the relay K and will close the pick-up circuit for relay PI. When the first train clears section CD, the relay R3 will become energized so that relay PI will be deenergized and relay J3 will be energized. Relay J3, however, requires a short interval of time to pick up which permits relay PI to reach its deenergized position so that when relay J3 does reach its picked-up position, the pick-up circuit for relay P3 is established over the back point of contact I8 of relay PI, instead of a stick circuit for relay PI over the front point of contact I8. In other words, the pick-up time'of relay J3 is sufficient to permit relay J I to become released so that even if relay RI does become released at the same instant relay R3 becomes energized, the relay PI has an opportunity to become released and thereby establish the pick-up circuit for the relay P3. The second train, therefore, upon occupying section CD will close a stick circuit for relay P3 so that the signal S will not be operated while such train is receding from the crossing although relays R3 and J3 will be released.

In the event of a momentary failure of a track circuit the apparatus embodying our invention will function in a manner similar to that just described for the two trains occupying sections AB and CD, respectively. For example, if track relay R3 should become momentarily deenergized and then become energized just at the moment a train enters section A-B, the pick-up time of relay J3 will be such that the relay PI will become released before front contact I! of relay J3 becomes closed so that the pick-up circuit for relay P3 is established inv going description that the apparatus functions in a manner similar to that just described for an eastbound train.

Although we'have shown apparatus embodying our invention applied to a singletrack, it is readily apparent to'those skilled in the art that, if desired, the relay K may be controlled from more than one track by apparatus exactly similar to that shown for track X.

Apparatus embodying our invention provides a simple and reliable means for operating a highway crossing signal in which operation of the signal is provided for an approaching train even though the operation of the signal may have been initiated by another train which does not proceed over the crossing. Furthermore, our invention provides for proper operation of the signal for anapproaching train even if such operation isinitiated by a momentary track circuit failure.

Although we have herein shown and described only one form of apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, a stretch of railway track divided into a first section and a second section, a signal, a signal control relay, a first track relay operable by a car entering said first section for controlling said signal control relay, a second track relay operable by a car entering said second section for controlling said signal control relay, a stick relay for each track relay each such stick relay efiective at times to prevent control of said signal control relay by the associated track relay, and a track repeating relay for each track relay for controlling said stick relays jointly with said track relays.

2. In combination, a stretch of railway track divided into a first section and a third section separated from each other by a second section intersected by a highway, a signal for controlling trafiic over said highway at such intersection, a signal control relay, a first trackrelay associated with said first section for controlling said signal control relay, a second track relay associated with said second section for controlling said signal control relay, a third track relay associated with said third section for controlling said signal control relay, a track repeating relay for each of said first and said third track relays, and means including said track repeating relays for causing said first and said third track relays to be effective for controlling said signal control relay for traflic moving only towards said highway.

3. In combination, a stretch of railway track divided into a first section and a second section separated from said first section by another section intersected by a highway, a signal for controlling traffic over said highway at such intersection, a signal control relay, a first track relay associated with said first section for controlling said signal for railway traffic moving over said stretch in one direction, a second track relay associated with said second section for controlling said signal for railway traific moving over said stretch in an opposite direction, another track relay associated with said other section for controlling said signal for railway traffic movingover said stretch in either direction, two repeating relays one associated with each of said first and second sections, two stick :relays one associated with each of said first and second sections and each controlled jointly by said three track relays, and a circuit for said signal control relay controlled jointly by said first and second and third track relays as well as by the associated repeating relays and the associated stick relays.

4. In combination, a stretch of railway track intersected by a highway, said track being divided to form three sections, a track relay for each section, a repeating relay for each of twoof said track relays, a signal control relay controlled in part by said three track relays, two stick relays one for each of two of said track relays for at times preventing the control of said signal control relay by the associated track relay, and a highway crossing signal located at said intersection and controlled by said signal control relay.

5. In combination, a stretch of railway track divided into three sections, a track relay for each section, two repeating relays one associated with each of two of said track relays, two stick relays one associated with each of such two track relays, a signal, a signal control relay, a first circuit for said signal control relay including a front contact of each track relay and a front contact of each repeating relay, a second circuit for said signal control relay including a front contact of the stick relay associated with one of said track relays, and a third circuit for said signal control relay including a front contact of the stick relay associated with the other of said track relays.

6. In combination, a stretch of railway track intersected by a highway, said track being divided into a first and a second and a third section, a track relay for each section, two repeating relays one controlled by the track relay for the first section and one controlled by the track relay for the third section, two stick relays one associated with the track relay for the first section and one associated with the track relay for the thirdsection, a pick-up circuit for one stick relay including a back contact of the track relay for the first section and a front contact of the repeating relay controlled by the track relay for the third section as well as a back contact of the other stick relay, a first stick circuit for said one stick relay including its own front contact and a back contact of the track relay for the second section, a second stick circuit for said one stick relay including its own front contact and a front contact of the repeating relay controlled by the track relay for the first section as well as a back contact of the track relay for the third section, and a signal for said highway controlled at times by said stick relays.

7. In combination, a stretch of railway track divided into two outer sections and an intermediate section, said intermediate section being intersected by a highway, a signal for controlling traflic over said highway at such intersection, a track circuit including a track relay for each section, two repeating relays one for each track relay for the outer sections, and means governed jointly by said track relays and by said repeating relays for causing said signal to operate for railway trafiic moving in either direction in said intermediate section but to operate only for railway trafiic moving toward the intersection in said two outer 'sections.

8. In combination, a stretch of railway track divided into two other sections and an intermediate section, said intermediate section being intersected by a highway, a signal for controlling trafiic over said highway at such intersection, a track circuit including a track relay for each section, two repeating relays one for each track relay for the outer sections, and means governed jointly by said track relays and by said repeating relays for causing said signal to operate when said intermediate section becomes occupied by a train moving in either direction and for causing said signal to operate when either of said outer sections becomes occupied by a train moving toward the intersection regardless of Whether the other outer section is then occupied or unoccupied.

9. In combination, a stretch of railway track divided into two outer sections and an intermediate section, said intermediate section being intersected by a highway, a signal for controlling traific over said highway at such intersection, a track circuit including a track relay for each section, two repeating relays one for each track relay for the outer sections, and means governed jointly by said track relays and by said repeating relays for initiating the operation of said signal when one of said outer sections becomes occupied by a train 'moving toward the intersection and for continuing such operation when the other of said outer sections becomes occupied by another train moving toward the intersection even though said first mentioned outer section then becomes unoccupied. RONALD A. McCANN. HENRY S. YOUNG. 

